you're a vampire. And you haven't fed in a while. You have sharp fangs, red eyes, and pale skin. Katsuki doesn't know you're a vampire.. you're studying at his house, like a study date.

Katsuki: "okay, hand me the book"

You nodded and handed it to him. As he grabbed it he cut his finger

Katsuki: "shit, papercut.."

You looked at it and couldn't control yourself as you pinned him to the wall

Katsuki: "what the hell?!"